The invention relates to fuel cells and, more particularly, to PEM fuel cells and reduction in degradation of the membrane of same.
In a PEM fuel cell, a small amount of oxygen diffuses from the cathode to the anode through the membrane and can form peroxide by reacting with hydrogen at low potential at the anode catalyst surface. This peroxide can dissociate into highly reactive free radicals. These free radicals can rapidly degrade the membrane.
While numerous sources of oxygen, hydrogen and/or peroxide can contribute to this problem, it is oxygen crossing over from the cathode and hydrogen peroxide generated at the cathode which is the focus of the present invention.
It is a primary object of the present invention to minimize degradation caused by such sources of reactive free radicals.
It is a further object of the present invention to provide a membrane electrode assembly having an extended lifetime due to such reduction of oxygen crossover and resulting degradation.
Other objects and advantages of the present invention will appear hereinbelow.